The FIRST award project proposed is a study of motor learning in Parkinson's disease (PD) and in Olivopontocerebellar atrophy (OPCA). The research would fill a major void in knowledge of these two movement disorders, since there is almost no information concerning the ability of these patients to attenuate motor deficits with practice. This is in spite of theoretical and animal studies which attribute some motor learning functions to the cerebellum. While the basal ganglia's role in motor learning is not understood, a preliminary study conducted by the P.I. indicated learning effects associated with preprogramming of movements. The study's rationale is threefold: 1) it will allow inferences concerning the role of the basal ganglia and cerebellum in motor learning; 2) residual motor control deficits in each disease following extensive practice will be described; 3) knowledge which may promote rehabilitation efforts in these disease groups may be forthcoming. A principal feature of these studies is the attempt to go beyond simple description of performance changes with practice. Tasks will emphasize specific motor processes, and analyses will focus on which processes can be improved. Secondly, practice will be structured so that feedback pertinent to each task is provided using an optimal schedule. A total of 160 PD, OPCA and control subjects will participate in 9 experiments. All will attempt to learn a rapid sequential aiming task in which the three-dimensional kinematics of hand motions are recorded. The goal will be to determine if the groups differentially improve in their respective disrupted processes, such as programming as opposed to directional accuracy. Each subject will also participate in one of 8 additional experiments which focus on reducing deficits of PD (motor programming, bradykinesia, difficulties with sequential and simultaneous movements, production of visually 'open-loop' motions) or OPCA (dysmetria, to meet novel conditions). The research extends the applicant's previous studies of psychomotor deficits in Parkinson's disease, and draws on the expertise and patient populations of two University of Michigan neurologists with special knowledge of each disease.